Identification of fungi isolated from banana rachis and characterization of their surface activity

Abstract

Filamentous fungi are an unexplored source for the production of biosurfactants, but over a decade one of the most surface active molecules called hydrophobins was discovered. There are few techniques to determine the surface activity of fungi without any kind of manipulation that can affect the final results. In this work, we identified 33 strains of filamentous fungi isolated from banana rachis which may have potential in producing biosurfactants. Further, the production of surface active compounds by the strains was measured by two techniques. First, the surface tension of supernatants was evaluated in liquid cultures of the strains. We found that three strains belonging to the genus Fusarium, Penicillium and Trichoderma showed activity in the reduction of surface tension, which indicate a putative production of biosurfactants. Second, we measured the contact angle between the drop of water and the solid culture of strains to determine the surface activity of cells, classifying the strains as hydrophilic or hydrophobic. These techniques can be used as a quantitative measurement of the surface activity of fungi without cell manipulation.